Mzabuni atasaini nukuu ya bei.

Atasaini is made of three parts:

• a- = subject marker for he/she or a singular person noun
• -ta- = future tense marker, will
• saini = verb stem from kusaini, to sign

So atasaini means he/she will sign.

Swahili does not mark gender in the third-person singular verb form.
So a- can refer to he or she.

In this sentence, mzabuni tells you who the subject is, but the verb itself still does not show gender.

Mzabuni is a singular noun referring to a person. It belongs to the m-/wa- noun class, which is the common class for people.

That matters because it controls agreement in the verb:

• mzabuni atasaini = the bidder will sign
• wazabuni watasaini = the bidders will sign

Notice how the verb changes from a- to wa- when the subject becomes plural.

Ya is the connector meaning something like of.
Swahili changes this connector to match the first noun.

Here, the first noun is nukuu, and for that noun class the connector is ya.

So:

• nukuu ya bei = literally quotation of price
• more naturally in English: price quotation or price quote

Literally, it means quotation of price.

In more natural English, that would usually be:

• price quotation
• price quote
• sometimes quoted price, depending on context

So the structure is very normal in Swahili: noun + of + noun.

Yes, it is basically Subject – Verb – Object:

• Mzabuni = subject
• atasaini = verb
• nukuu ya bei = object

So the sentence structure is very close to English:

• The bidder / will sign / the price quotation

In Swahili, tense is usually built into the verb, not added as a separate word.

So instead of writing a separate word for will, Swahili uses the future marker -ta- inside the verb:

• atasaini = a- + -ta- + saini
• literally: he/she-will-sign

This is very common in Swahili verbs.

Swahili normally does not use articles like the or a/an.

That means mzabuni can mean:

• a bidder
• the bidder

And nukuu ya bei can mean:

• a price quotation
• the price quotation

The exact meaning depends on context.

Yes. Kusaini is a loanword based on English sign.

This is common in Swahili, especially with modern or administrative vocabulary.
Once you know kusaini means to sign, forms like atasaini become much easier to recognize.

A simple pronunciation guide is:

• Mzabuni = m-za-BU-ni
• atasaini = a-ta-sa-I-ni
• nukuu = nu-KUU
• ya = ya
• bei = roughly bay

A few helpful points:

• Swahili vowels are usually pronounced clearly and consistently.
• ai in saini is pronounced as two vowel sounds, roughly sa-i-ni.
• nukuu has a long uu sound.

Because the object is already stated clearly after the verb: nukuu ya bei.

In Swahili, you do not have to add an object marker when the full object noun is present, especially in a simple sentence like this.

So atasaini nukuu ya bei is completely normal as it stands.